Proportion-calculator.



M. CASHMORE.

PROPORTION CALCULATOR.

APPLICATION FILED 05c. 31. I914.

1,163,392. Patented Dec. 7, 1915.

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83M, mgr umalz W MONTAGUE CASHMORE, OF LONDON, ENGLAND.

PROPORTION-CALCULATOR.

Specification of Letters Patent.

Patented Dec. 7,1915.

Application filed December 31, 1914. Serial No. 879,898.

T 0 all whom it may concern:

Be it known that I, MONTAGUE CASHMORE, a subject of the King of England,residing at Maida Vale, London, England, have invented certain new anduseful Improvements in Proporti0n-Calculators, of which the following isa specification.

This invention relates to proportion calculators in which a two-armedmember or its equivalent providing an angle (conveniently a right angle)between the arms is employed, one of which arms is a straight guide, amovable member is pivoted by one end to the guide-arm or its equivalentso that its other end can swing along the other arm, a strut-member isprovided which can be adjusted along a guide-arm whence it projectsacross the pivoted member and has a scale to indicate how far thismember is moved from the arm to which it is pivoted, the saidstrut-member having moreover a constant angular relation to the saidguidearm, a scale is provided on the guide-arm to indicate how far thestrut-member is moved along it and a further scale is provided on thearm swept by the pivoted member so that after the strut-member has beenset along one arm to a position indicating one term of a proportionstated, and the pivoted member has been moved along the strutmember to aposition indicating the second term of the proportion stated, the fourthterm can be read olt from the scale on the other arm swept by themovable member.

The object of my invention is to provide a proportion calculator havinga strut-member which has a sliding movement relatively to the directionof length of one arm of a two-armed member a nd also sliding movement ina direction transverse to the arm in whose direction of length it hassliding movement, said strut-member being so arranged as to constitute apositive stop for the pivoted member in one direction, the position ofsuch stopping point varying according to the setting of thestrut-member, and the strut-member further having an index or readingedge which cooperates with the same scale as the free end of the movablemember so that the one scale will serve to position the strut for one ofthe terms of the proportion stated and will also indicate the fourthterm of such proportion when the strut has been further adjusted for thesecond term of the proportion stated.

Preferably the strut-member is permanently mounted on its guide-arm sothat it slides along the same and maintains a constant angle thereto,and the pivoted member is provided with a straight guide portion whichabuts against the strut-member.

The accompanying drawing illustrates diagrammatically one method ofcarrying out this invention.

A two-armed member A is employed providing a right angle between thesaid arms. For convenience one arm A may be termed the horizontal armand the other arm A may be termed the vertical arm. These are providedrespectively with graduated edges or scales A A*. On the arm A at apoint A in line with the inner edge of the same, is pivoted a movablemember B. This may be termed the hypotenuse member and it extends acrossto the vertical arm A and has a lower or inner edge B in line with thepivot A the position of which can be read off against the graduations ofthe scale A*. The horizontal arm A is machined to provide a straightsliding surface for a block C carried thereon in any convenient manner.A strut-member D slides in the block C in a direction at right angles tothe arm A and parallel to the arm A The end of one edge D of the strutcontacts at D with the edge B of the hypotenuse member B. The strut hasa right-angled extension D having an upper edge D in line With the pointD This extension slides through a block E free to slide on the verticalarm A which is also machined for this purpose. Thumb-screws C and E areprovided to clamp the blocks C and E in any desired position upon theirrespective arms, and if desired a bolt D sliding in a slot in the memberB may also be provided to clamp the member D to the hypotenuse member B.The graduations along the horizontal edge A commence at zero at thepoint A and between this point and the point A where the edges A and Aintersect, the graduations have some number of parts Which affords easymanipulation in calculation, say, for example, one hundred.

In using the device, the graduations of the scale A are used to indicateone term of theproportion stated, by setting the vertical edge D of themember D thereto. The graduations on the vertical edge A are used torepresent the second term of the proportion by setting the upper edge Dof the extension D at the graduation corresponding to the desired secondterm. If the hypotenuse member is then made to bear upon the point D,its point of intersection with the scale A will indicate the fourth termof the proportion. The total number 100 of the graduations on the edge Ais the third term of the proportion. Thus if it is required to know theproportion of the cost of labor as compared with the total cost ofproduction of any article, the block C can be set to a number of unitsfrom zero representing the total cost, and the strut D run out away fromthe arm A until the block E is brought into a position representing onthe scale A the cost of labor. If the hypotenuse member B is made tobear on the strut at D the edge B will be found to intersect the edge Aat a point which will indicate the proportion required. The reading ofthe edge B on the scale A will, of course, need to be taken in itsproper relation to the scale on the horizontal arm. Thus, if as shownthere are one hundred units between the points A and A on the edge A theunits on the scale A will, when read against the edge B representhundredths in the required answer and may be read as percentages.

The clamping screws C and E are used to fix the blocks'C and E in anyadjusted position and are useful particularly when one of the first twoterms-of the proportion stated is a fixed quantity, and a series ofresults are required to be obtained with various values of the otherterm. The free end of the hypotenuse member B may be provided with means(not shown) for clamping it to the vertical arm A This last clampingmeans is serviceable Where the use of the instrument is reversed and itis desired to start operations with a given percentage as constitutingone of the terms of the proportion whereof another term is to be found.Thus, if goods are bought at a certain price and it is desired to put acertain percentage of profit on them, the strut D may be adjusted alongthe scale A to a position representing the price of the goods, and thehypotenuse member B may be clamped to the arm A at the positionrepresenting the percentage of profit required, and then when the strutis run out through the block C; until it contacts'with the edge B of thehypotenuse, the selling price can be read off on the scale A. 1

Obviously the device can be varied in the details of manufacture. Forexample, one of the limbs of the strut-member D instead of being passedthrough the block C could be made to merely lie across the arm A of thetwo-armed member A- to serve as an index thereon.

It will be understood that hypotenuse is used throughout thespecification to indicate the member providing the third side of thetriangle formed by the edges A A, B whether this is a right-angledtriangle or not.

What I claim as my invention and desire strut-member along its guideWhile maintaining it at a constant angle to the said guide, means forsliding the strut-member across its guide in such direction as to causeit to project a greater or less distance therefrom a scale, portion toindicate the position of the strut-member along its guide, a scale toindicate the amount it projects from the guide, and a scale-portionpositioned to serve as an index to the pivoted guide, for the purposedescribed.

2. In a proportion calculator the combination of, a straight guide, asecond straight guide pivotedgto move relatively to the first, astrut-member which projects laterally from one straight guide and abutsagainst the guiding portion of and forms a positive stop for the otherstraight guide to limit its movement in one direction, means foradjusting the strut-member along its guide while maintaining it at aconstant/angle to the said guide, means for sliding the strut-memberacross its guide in such direction as to cause it to project a greateror less distance therefrom, a scale to indicate the position of thestrut-member along its guide, and a second scale parallel to thetransverse sliding movement of the strut which latter is provided with areading edge lying across the second scale parallel to the guide alongwhich the strut slides to indicate on this scale in all positions of thestrut the amount which the strut projects from its guide, the pivotedguide being also provided with a reading edge which cooperates wit-h thesaid second scale so that the one scale can be employed for one of thesettings of the strut and to read off the result indicated by thepivoted guide.

3. In a proportion calculator, the combination of, a two-armed memberproviding an angle between the arms and whereof one arm is a straightguide, a second straight guide pivoted to one of thearms so that itsfree end can swing along the other arm, a strut-member which lies acrossthe straight guide-arm and arranged to slide across the same in a pathparallel to the other arm and abut against the guiding portion of andform a positive stop for the pivoted straight guide, means for adjustingthe str ut-member along its guide while maintaining the saidstrut-member at a constant angle to the said guide, a scale on the armalong which the free end of the pivoted straight guide sweeps, thestrut-member moreover having an index-portion which reads on said scaleto indicate how far it projects from its guide and a scale forindicating how far the strut-member is moved along its guide, for thepurpose described.

4. In a proportion calculator, the combination of, a 'two-armcd memberwhose arms provide an angle between them each arm forming a straightguide, a third straight guide pix'oted at one end to one of the saidarms so that the free end of the movable guide can move along the arm towhich it is not pivoted, a strut-member comprising two arms which areparallel to the two straight guide-arms and cross the same root of thetwo arms being made to abut against the guiding portion of the pivotedguide to form a positive stop therefor when moved in one direction,means for slidingly connecting the two arms of the strutmen1ber with thetwo straight guide-arms so that the strut-member can slide both alongand across either arm without changing its angular position relativelyto the arms, a scale on the arm to which the movable member is pivoted,and a Scale on the other arm which serves the double purpose of readingagainst the strut and the free end of the said movable arm, for thepurpose described.

In testimony whereof I have signed my name to this specification in thepresence of 5 two subscribing witnesses.

MONTAGUE CASHMORE. Witnesses:

HARRY B. BRIDGES, STANLEY R. Moons.

